1. Technical Field
The present invention pertains to the area of safety systems for ship crews to locate persons who have fallen overboard or are lost at sea, to alert emergency networks and to facilitate rescue. More particularly the invention concerns a method and device for alert and distress location, and a distress locating beacon.
2. Prior Art
In the area of sea safety, a device is known through international application WO-98/38083 in the name of the applicant, for modifying a vessel's bearing. This device comprises a radio transmitter worn by a yachtsman and a radio receiver able to act upon the compass of an automatic pilot via a command circuit. The command circuit is able to deviate the magnetic compass needle towards a fictitious North via inductive coils arranged around the compass.
This device is set in operation during a sea race when the automatic pilot is in action, and the yachtsman is intended to wear the transmitter permanently. The receiver permanently captures the radio signal generated by the transmitter since the yachtsman is on board the boat. Should the yachtsman fall overboard, the radio link between the immersed transmitter and the onboard receiver is cut off. The receiver detects the absence of a signal and acts on the command circuit to deviate the magnetic compass needle towards a fictitious North. The automatic pilot then seeks to correct its route setting and acts on the boat rudders to change course. The boat then starts turning indefinitely in circles around the point where the person fell overboard.
This device for correcting a vessel's course is especially indicated for single-handed boat races. It is particularly suitable for light sailing vessels.
For racing sailing vessels however, at speeds as high as 40 knots (75 km/h) or 50 knots (53 km/h) the speeds currently being reached, a sudden change of course is prohibited. However use of the device for changing a vessels' course has heightened the need for a safety device for yachtsmen taking part in single-handed races.
Further to a series of recent accidents at sea both on single-handed and crewed racing vessels as well as on fishing vessels, the demand for a suitable safety device has become mandatory.
For fishing vessels, commercial vessels and heavy surface craft, the inertia is too high for a sudden change in course to be made and take up circular movement around a point where a person has been lost at sea.
The subject of the present invention is therefore the development of a new safety device for vessel crews intended to facilitate the rescue of overboard persons.
One objective of the invention is to enable the accurate locating of any overboard person.
A further subject of the invention is the automatic transmission of a distress signal to be captured and retransmitted by rescue networks so as to alert other nearby vessels, rescue centres and even aircraft within the area.